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A compound of the formula (I)
##STR1##
wherein n is an integer from 1 to 4; the radicals R.sub.1 are for example
a group of the formula
##STR2##
R.sub.3 is for example hydrogen, C.sub.1 -C.sub.8 alkyl or C.sub.5
-C.sub.12 cycloalkoxy; Z and R.sub.2 are for example a group
##STR3##
the radicals A and E are, for example, independently of one another
--N(R.sub.11)(R.sub.12) or a group of the formula
##STR4##
R.sub.11 and R.sub.12 are for example C.sub.1 -C.sub.12 alkyl; R.sub.13
has for example one of the meanings given for R.sub.3 ; E* has for example
one of the meanings given for A or is a group of the formula
##STR5##
The compounds of the formula (I) are useful as light stabilizers, heat
stabilizers and oxidation stabilizers for organic materials, in particular
synthetic polymers such as polyolefins.

1. A compound of the formula (I) ##STR49## wherein n is 1 or 2; the radicals R.sub.1 are independently of one another hydrogen, C.sub.1 -C.sub.8 alkyl, C.sub.5 -C.sub.12
cycloalkyl unsubstituted or substituted by 1, 2 or 3 C.sub.1 -C.sub.4 alkyl; or a group of the formula (II), ##STR50## with the proviso that at least one of the radicals R.sub.1 is a group of the formula (II);

Z is a group of the formula (IIIa) or (IIIb); ##STR51## R.sub.4, R.sub.8 and R.sub.9 are independently of one another C.sub.1 -C.sub.4 alkyl or C.sub.5 -C.sub.12 cycloalkyl unsubstituted or substituted by 1, 2 or 3 C.sub.1 -C.sub.4 alkyl;

R.sub.5, R.sub.6 and R.sub.7 are independently of one another hydrogen or C.sub.1 -C.sub.4 alkyl;

m is zero or an integer from 1 to 6;

p is 1 or 2;

R.sub.2 is a group of formula (IIIa) or is C.sub.2 -C.sub.12 alkylene, C.sub.5 -C.sub.7 cycloalkylene,

C.sub.5 -C.sub.7 cycloalkylenedi(C.sub.1 -C.sub.4 alkylene), C.sub.1 -C4alkylenedi(C.sub.5 -C.sub.7 cycloalkylene), phenylene-di(C.sub.1 -C.sub.4 alkylene) or C.sub.4 -C.sub.12 alkylene interrupted by 1,4-piperazinediyl or >N--X.sub.1 with
X.sub.1 being C.sub.1 -C.sub.12 acyl or (C.sub.1 -C.sub.8 alkoxy)carbonyl or having one of the meanings given for R.sub.1 except hydrogen;

the radicals A are independently of one another --OR.sub.10, --N(R.sub.11)(R.sub.12) or a group of the formula (IV); ##STR52## R.sub.10, R.sub.11 and R.sub.12 are independently of one another hydrogen, C.sub.1 -C.sub.12 alkyl, C.sub.5 -C.sub.12
cycloalkyl unsubstituted or substituted by 1, 2 or 3 C.sub.1 -C.sub.4 alkyl; C.sub.3 -C.sub.12 alkenyl, phenyl unsubstituted or substituted by 1, 2 or 3 C.sub.1 -C.sub.4 alkyl or C.sub.1 -C.sub.4 alkoxy; C.sub.7 -C.sub.9 phenylalkyl unsubstituted or
substituted on the phenyl by 1, 2 or 3 C.sub.1 -C.sub.4 alkyl or C.sub.1 -C.sub.4 alkoxy; tetrahydrofurfuryl or C.sub.2 -C.sub.4 alkyl substituted in the 2, 3 or 4 position by --OH, C.sub.1 -C.sub.9 alkoxy or a group of the formula (V) ##STR53## with Y
being --O--, --CH.sub.2 --, --CH.sub.2 CH.sub.2 -- or >N--CH.sub.3 ;

or --N(R.sub.11)(R.sub.12) is additionally a group of the formula (V), with the proviso that Y is not >N--CH.sub.3 ;

R.sub.13 has one of the meanings given for R.sub.3 ;

X.sub.2 is --O-- or >N--R.sub.14 ;

R.sub.14 is hydrogen, C.sub.1 -C.sub.12 alkyl, C.sub.5 -C.sub.12 cycloalkyl unsubstituted or substituted by 1, 2 or 3 C.sub.1 -C.sub.4 alkyl; C.sub.7 -C.sub.9 phenylalkyl unsubstituted or substituted on the phenyl by 1, 2 or 3 C.sub.1 -C.sub.4
alkyl or C.sub.1 -C.sub.4 alkoxy; tetrahydrofurfuryl, a group of the formula (II) or C.sub.2 -C.sub.4 alkyl substituted in the 2, 3 or 4 position by --OH, C.sub.1 -C.sub.8 alkoxy, di(C.sub.1 -C.sub.4 alkyl)amino or a group of the formula (V);

the radicals E have independently of one another one of the meanings given for A; and

E* has one of the meanings given for A or is a group of the formula (VI) ##STR54## with A, E, RI and Z being as defined above; with the proviso that, when n is 2, each of the radicals E*, R.sub.1 and R.sub.2 in the repetitive units can have the
same or a different meaning.

the radicals R.sub.1 are independently of one another hydrogen, C.sub.1 -C.sub.4 alkyl, C.sub.5 -C.sub.8 cycloalkyl unsubstituted or substituted by methyl; or a group of the formula (II) with the proviso that at least one of the radicals R.sub.1
is a group of the formula (II);

R.sub.4, R.sub.8 and R.sub.9 are independently of one another C.sub.1 -C.sub.4 alkyl or cyclohexyl;

R.sub.5, R.sub.6 and R.sub.7 are hydrogen;

m is zero or an integer from 1 to 3;

R.sub.2 is a group of the formula (IIIa) or is C.sub.2 -C.sub.8 alkylene, cyclohexylene, methylene-cyclohexylene-methylene, cyclohexylene-methylene-cyclohexylene or methylene-phenylene-methylene;

R.sub.10, R.sub.11 and R.sub.12 are independently of one another hydrogen, C.sub.1 -C.sub.8 alkyl, C.sub.5 -C.sub.8 cycloalkyl unsubstituted or substituted by methyl; C.sub.3 -C.sub.8 alkenyl, phenyl unsubstituted or substituted by methyl;
benzyl, tetrahydrofurfuryl or C.sub.2 -C.sub.3 alkyl substituted in the 2 or 3 position by --OH, C.sub.1 -C.sub.4 alkoxy, or 4-morpholinyl; or

--N(R.sub.11)(R.sub.12) is additionally 4-morpholinyl;

R.sub.14 is hydrogen, C.sub.1 -C.sub.8 alkyl, C.sub.5 -C.sub.8 cycloalkyl unsubstituted or substituted by methyl; benzyl, tetrahydrofurfuryl, a group of the formula (II) or C.sub.2 -C.sub.3 alkyl substituted in the 2 or 3 position by --OH,
C.sub.1 -C.sub.4 alkoxy, dimethylamino, diethylamino or 4-morpholinyl.

6. A compound of the formula (I) according to claim 1 wherein

the radicals R.sub.1 are independently of one another hydrogen, C.sub.1 -C.sub.4 alkyl, cyclohexyl or a group of the formula (II) with the proviso that at least one of the radicals R.sub.1 is a group of the formula (II);

Z is a group of the formula (IIIa);

R.sub.4 is C.sub.1 -C.sub.4 alkyl;

R.sub.5, R.sub.6 and R.sub.7 are hydrogen;

m is zero or 1;

R.sub.2 is a group of the formula (IIIa) or is C.sub.2 -C.sub.8 alkylene;

A is --N(R.sub.11)(R.sub.12) or a group of the formula (IV);

R.sub.11 and R.sub.12 are independently of one another hydrogen, C.sub.1 -C.sub.8 alkyl, cyclohexyl, phenyl, benzyl, tetrahydrofurfuryl, 2-hydroxyethyl or 2-methoxyethyl; or

--N(R.sub.11)(R.sub.12) is additionally 4-morpholinyl;

X.sub.2 is >N--R.sub.14 ;

R.sub.14 is hydrogen, C.sub.1 -C.sub.8 alkyl, cyclohexyl, benzyl, tetrahydrofurfuryl, a group of the formula (II), 2-hydroxyethyl or 2-methoxyethyl.

7. A compound of the formula (I) according to claim 1 wherein

n is 1 or 2;

the radicals R.sub.1 are a group of the formula (II);

Z is a group ##STR55## R.sub.2 is a group of the formula (IIIa); R.sub.3 is hydrogen, C.sub.1 -C.sub.4 alkyl or C.sub.5 -C.sub.8 cycloalkoxy;

A is --N(R.sub.11)(R.sub.12) or a group of the formula (IV);

R.sub.11 and R.sub.12 are independently of one another C.sub.1 -C.sub.4 alkyl;

X.sub.2 is >N--R.sub.14 ; and

R.sub.14 is C.sub.1 -C.sub.4 alkyl.

8. A compound of the formula (I) according to claim 1 which corresponds to the formula ##STR56##

9. A compound of the formula (I) according to claim 1 which corresponds to the formula

10. A composition containing an organic material susceptible to degradation induced by light, heat or oxidation and at least one compound of the formula (I) according to claim 1.

11. A composition according to claim 10 wherein the organic material is a synthetic polymer.

12. A composition according to claim 10 wherein the organic material is polyethylene or polypropylene.

13. A method for stabilizing an organic material against degradation induced by light, heat or oxidation, which comprises incorporating therein an effective stabilizing amount of at least one compound of the formula (I) according to claim 1.

Description

This invention relates to triazine derivatives containing 2,2,6,6-tetramethyl-4-piperidyl groups, to their use as light stabilizers, heat stabilizers and oxidation stabilizers for organic
materials, particularly synthetic polymers, and to the organic materials thus stabilized.

The stabilization of synthetic polymers with derivatives of 2,2,6,6-tetramethylpiperidine has been described for example in U.S. Pat. No. 4,086,204, U.S. Pat. No. 4,234,707, U.S. Pat. No. 4,331,586, U.S. Pat. No. 4,335,242, U.S. Pat.
No. 4,459,395, U.S. Pat. No. 4,492,791, U.S. Pat. No. 4,847,380, U.S. Pat. No. 5,198,546, U.S. Pat. No. 5,455,347, EP-A-53 775, EP-A-357 223, EP-A-377 324 and EP-A-488 502.

This invention relates in particular to a compound of the formula (I) ##STR6## wherein n is an integer from 1 to 4; the radicals R.sub.1 are independently of one another hydrogen, C.sub.1 -C.sub.8 alkyl, C.sub.5 -C.sub.12 cycloalkyl unsubstituted
or substituted by 1, 2 or 3 C.sub.1 -C.sub.4 alkyl; or a group of the formula (II), ##STR7## with the proviso that at least one of the radicals R.sub.1 is a group of the formula (II);

Z is a group of the formula (IIIa) or (IIIb); ##STR8## R.sub.4, R.sub.8 and R.sub.9 are independently of one another C.sub.1 -C.sub.4 alkyl or C.sub.5 -C.sub.12 cycloalkyl unsubstituted or substituted by 1, 2 or 3 C.sub.1 -C.sub.4 alkyl;

R.sub.5, R.sub.6 and R.sub.7 are independently of one another hydrogen or C.sub.1 -C.sub.4 alkyl;

m is zero or an integer from 1 to 6;

p is 1 or 2;

R.sub.2 has one of the meanings given for Z or is C.sub.2 -C.sub.12 alkylene, C.sub.5 -C.sub.7 cycloalkylene, C.sub.5 -C.sub.7 cycloalkylenedi(C.sub.1 -C.sub.4 alkylene), C.sub.1 -C.sub.4 alkylenedi(C.sub.5 -C.sub.7 cycloalkylene),
phenylenedi(C.sub.1 -C.sub.4 alkylene) or C.sub.4 -C.sub.12 alkylene interrupted by 1,4-piperazinediyl, --O-- or >N--X.sub.1 with X.sub.1 being C.sub.1 -C.sub.12 acyl or (C.sub.1 -C.sub.8 alkoxy)carbonyl or having one of the meanings given for R.sub.1

except hydrogen;

the radicals A are independently of one another --OR.sub.10, --N(R.sub.11)(R.sub.12) or a group of the formula (IV); ##STR9## R.sub.10, R.sub.11 and R.sub.12 are independently of one another hydrogen, C.sub.1 -C.sub.12 alkyl, C.sub.5 -C.sub.12
cycloalkyl unsubstituted or substituted by 1, 2 or 3 CG-C.sub.4 alkyl; C.sub.3 -C.sub.12 alkenyl, phenyl unsubstituted or substituted by 1, 2 or 3 C.sub.1 -C.sub.4 alkyl or C.sub.1 -C.sub.4 alkoxy; C.sub.7 -C.sub.9 phenylalkyl unsubstituted or
substituted on the phenyl by 1, 2 or 3 C.sub.1 -C.sub.4 alkyl or C.sub.1 -C.sub.4 alkoxy; tetrahydrofurfuryl or C.sub.2 -C.sub.4 alkyl substituted in the 2, 3 or 4 position by --OH, C.sub.1 -C.sub.8 alkoxy, di(C.sub.1 -C.sub.4 alkyl)amino or a group of
the formula (V) ##STR10## with Y being --O--, --CH.sub.2 --, --CH.sub.2 CH.sub.2 -- or >N--CH.sub.3 ;

or --N(R.sub.11)(R.sub.12) is additionally a group of the formula (V);

R.sub.13 has one of the meanings given for R.sub.3 ;

X.sub.2 is --O-- or >N--R.sub.14 ;

R.sub.14 is hydrogen, C.sub.1 -C.sub.12 alkyl, C.sub.5 -C.sub.12 cycloalkyl unsubstituted or substituted by 1, 2 or 3 C.sub.1 -C.sub.4 alkyl; C.sub.7 -C.sub.9 phenylalkyl unsubstituted or substituted on the phenyl by 1, 2 or 3 C.sub.1 -C.sub.4
alkyl or C.sub.1 -C.sub.4 alkoxy; tetrahydrofurfuryl, a group of the formula (II) or C.sub.2 -C.sub.4 alkyl substituted in the 2, 3 or 4 position by --OH, C.sub.1 -C8alkoxy, di(C.sub.1 -C.sub.4 alkyl)amino or a group of the formula (V);

the radicals E have independently of one another one of the meanings given for A; and E* has one of the meanings given for A or is a group of the formula (VI) ##STR11## with A, E, R.sub.1 and Z being as defined above; with the proviso that, when
n is 2, 3 or 4, each of the radicals E*, R.sub.1 and R.sub.2 in the repetitive units can have the same or a different meaning.

Each of the radicals E*, R.sub.1 and R.sub.2 has preferably the same meaning in the several repetitive units of the formula (I).

Examples of alkenyl containing not more than 12 carbon atoms are allyl, 2-methylallyl, butenyl, hexenyl, undecenyl and dodecenyl. Alkenyls in which the carbon atom in the 1-position is saturated are preferred, and allyl is particularly
preferred.

Examples of C.sub.7 -C.sub.9 phenylalkyl which is unsubstituted or substituted on the phenyl by 1, 2 or 3 C.sub.1 -C.sub.4 alkyl or C.sub.1 -C.sub.4 alkoxy are benzyl, methylbenzyl, methoxybenzyl, dimethylbenzyl, trimethylbenzyl, t-butylbenzyl
and 2-phenylethyl. Benzyl is preferred.

Z is preferably a group of the formula (IIIa) with R.sub.5, R.sub.6 and R.sub.7 being hydrogen.

m is preferably zero or 1.

R.sub.2 and Z are preferably identical.

Compounds of the formula (I) which are preferred are those wherein

the radicals R.sub.1 are independently of one another hydrogen, C.sub.1 -C.sub.4 alkyl, C.sub.5 -C.sub.8 cycloalkyl unsubstituted or substituted by methyl; or a group of the formula (II) with the proviso that at least one of the radicals RI is a
group of the formula (II);

R.sub.4, R.sub.8 and R.sub.9 are independently of one another C.sub.1 -C.sub.4 alkyl or cyclohexyl;

R.sub.5, R.sub.6 and R.sub.7 are hydrogen;

m is zero or an integer from 1 to 3;

R.sub.2 has one of the meanings given for Z or is C.sub.2 -C.sub.8 alkylene, cyclohexylene, methylene-cyclohexylene-methylene, cyclohexylene-methylene-cyclohexylene or methylene-phenylene-methylene;

R.sub.10, R.sub.11 and R.sub.12 are independently of one another hydrogen, C.sub.1 -C.sub.8 alkyl, C.sub.5 -C.sub.8 cycloalkyl unsubstituted or substituted by methyl; C.sub.3 -C.sub.8 alkenyl, phenyl unsubstituted or substituted by methyl;
benzyl, tetrahydrofurfuryl or C.sub.2 -C.sub.3 alkyl substituted in the 2 or 3 position by --OH, C.sub.1 -C.sub.4 alkoxy, dimethylamino, diethylamino or 4-morpholinyl; or

--N(R.sub.11)(R.sub.12) is additionally 4-morpholinyl;

R.sub.14 is hydrogen, C.sub.1 -C.sub.8 alkyl, C.sub.5 -C.sub.8 cycloalkyl unsubstituted or substituted by methyl; benzyl, tetrahydrofurfuryl, a group of the formula (II) or C.sub.2 -C.sub.3 alkyl substituted in the 2 or 3 position by --OH,
C.sub.1 -C.sub.4 alkoxy, dimethylamino, diethylamino or 4-morpholinyl.

Compounds of the formula (I) which are particularly preferred are those wherein

the radicals R.sub.1 are independently of one another hydrogen, C.sub.1 -C.sub.4 alkyl, cyclohexyl or a group of the formula (II) with the proviso that at least one of the radicals R.sub.1 is a group of the formula (II);

Z is a group of the formula (IIIa);

R.sub.4 is C.sub.1 -C.sub.4 alkyl;

R.sub.5, R.sub.6 and R.sub.7 are hydrogen;

m is zero or 1;

R.sub.2 has one of the meanings given for Z or is C.sub.2 -C.sub.8 alkylene;

A is --N(R.sub.11)(R.sub.12) or a group of the formula (IV);

R.sub.11 and R.sub.12 are independently of one another hydrogen, C.sub.1 -C.sub.8 alkyl, cyclohexyl, phenyl, benzyl, tetrahydrofurfuryl, 2-hydroxyethyl or 2-methoxyethyl; or

--N(R.sub.11)(R.sub.12) is additionally 4-morpholinyl;

X.sub.2 is >N--R.sub.14 ;

R.sub.14 is hydrogen, C.sub.1 -C.sub.8 alkyl, cyclohexyl, benzyl, tetrahydrofurfuryl, a group of the formula (II), 2-hydroxyethyl or 2-methoxyethyl.

Compounds of the formula (I) which are of interest are those wherein

n is 1 or 2;

the radicals R.sub.1 are a group of the formula (II);

Z is a group ##STR16## R.sub.2 has one of the meanings given for Z; R.sub.3 is hydrogen, C.sub.1 -C.sub.4 alkyl or C.sub.5 -C.sub.8 cycloalkoxy;

A is --N(R.sub.11)(R.sub.12) or a group of the formula (IV);

R.sub.11 and R.sub.12 are independently of one another C.sub.1 -C.sub.4 alkyl;

X.sub.2 is >N--R.sub.14 ; and

R.sub.14 is C.sub.1 -C.sub.4 alkyl.

The compounds of the formula (I) may be prepared, for example, according to the methods shown in the following.

Method A:

When R.sub.2 has the same meaning as Z and the radicals E and E* have the same meanings, a compound of the formula (VII) ##STR17## may be prepared, for example, by reaction of a compound of the formula (VII) with an appropriate molar amount of a
compound of the formula (IX). ##STR18##

In more detail, when n is 1, a compound of the formula (VII) may be prepared, for example, according to Scheme A-1. ##STR19##

When n is 2, a compound of the formula (VII) may be prepared, for example, according to Scheme A-2. ##STR20##

When n is 3, a compound of the formula (VII) may be prepared, for example, according to Scheme A-3. ##STR21##

When n is 4, a compound of the formula (VII) may be prepared, for example, according to Scheme A-4. ##STR22##

Thereafter, the compounds of the formulae (VII-1), (VII-2), (VII-3) and (VII-4) are caused to react with the appropriate molar amounts of the compounds of the formulae (XV) and/or (XVI)

to obtain the corresponding compounds of the formula (I).

Method B:

When R.sub.2 has the same meaning as Z, the radical E* is different from the radicals E and the radical E* is also different from the group of the formula (VI), the compounds of the formulae (X), (XII), (XIII) and (XIV), depending on the value of
n=1, 2, 3 or 4, respectively, are first prepared according to METHOD A as described above.

Thereafter, these compounds are caused to react with the appropriate molar amounts of the compounds of the formula (XVII)

to give the compounds of the formula (XVIII) ##STR23## with n being 1, 2, 3 or 4, respectively.

Then, the compounds of the formula (XVIII) are caused to react with the appropriate molar amounts of the compound of the formula (IX) or (XIX) ##STR24## to obtain the corresponding compounds of the formula (XX) or (I). ##STR25## with n being 1,
2, 3 or 4, respectively.

When the compounds of the formula (XX) are obtained, these compounds are subsequently caused to react with the appropriate molar amounts of the compounds of the formulae (XV) and/or (XVI) to give the corresponding compounds of the formula (I).

The compounds of the formula (XIX) may be prepared by using well know synthesis procedures, for example, reacting the compound of the formula (IX) with the appropriate molar amounts of the compounds of the formulae (XV) and/or (XVI).

Method C:

When R.sub.2 has the same meaning as Z and the radical E* is a group of the formula VI, the compounds of the formulae (X), (XII), (XIII) and (XIV), depending on the value of n=1, 2, 3 or 4, respectively, are first prepared according to METHOD A
as described above.

Thereafter, these compounds are caused to react with the appropriate molar amounts of the compounds of the formula (VIII) to give the compounds of the formula (XXI) ##STR26## with n being 1, 2, 3 or 4, respectively.

Then, the compounds of the formula (XXI) are caused to react with the appropriate molar amounts of the compound of the formula (IX) or (XIX) to obtain the corresponding compounds of the formula (XXII) or (I). ##STR27##

When the compounds of the formula (XXII) are obtained, these compounds are subsequently caused to react with the appropriate molar amounts of the compounds of the formulae (XV) and/or (XVI) to give the corresponding compounds of the formula (I).

Method D:

When R.sub.2 is different from Z or at least one of the radicals R.sub.2 --in the recurring units (n=2, 3 or 4) of the compounds of the formula (I)--is different from Z, the compounds of the formula (XXIII) ##STR28## are first prepared by
reacting the compounds of the formula (XIX) with the equivalent molar amounts or an excess of the compounds of the formula (XXIV). ##STR29##

Thereafter, the compounds of the formula (XXIII) are caused to react with the appropriate molar amounts of the compounds of the formulae (XXV) and (XXIV) ##STR30## analogously to the method described for example in EP-A-782 994 to give the
compounds of the formula (XXVI). ##STR31##

Subsequently, when E* has the same meaning as E, the compounds of the formula (XXVI) are caused to react with the appropriate molar amounts of the compounds of the formula (XXVII) ##STR32## to give the compounds of the formula (XXVIII).
##STR33##

Then, the compounds of the formula (XXVIII) are caused to react with the appropriate molar amounts of the compounds of the formula (XV) to give the corresponding compounds of the formula (I).

When E* is different from E, the compounds of the formula (XXVI) are caused to react with the appropriate molar amounts of the compounds of the formula (XXV) to give the compounds of the formula (XXIX). ##STR34##

Thereafter, the compounds of the formula (XXIX) are caused to react with the appropriate molar amounts of the compounds of the formula (XXIII) to give the corresponding compounds of the formula (I).

Alternatively, the compounds of the formula (XXIX) are caused to react with the appropriate molar amounts of the compounds of the formula (VIII) and, thereafter, with the appropriate molar amounts of the compounds of the formula (XIX) to give the
corresponding compounds of the formula (I).

Alternatively again, the compounds of the formula (XXIX) are caused to react with the appropriate molar amounts of the compounds of the formula (VIII) and, thereafter, with the appropriate molar amounts of the compound of the formula (IX) to give
the compounds of the formula (XXX). ##STR35##

Thereafter, the compounds of the formula (XXX) are caused to react with the appropriate molar amounts of the compounds of the formulae (XV) and/or (XVI) to give the corresponding compounds of the formula (I).

The compounds of the formula (XXV) may be prepared by using well known synthesis processes, for example, by reacting the compound of the formula (IX) with the appropriate molar amounts of the compounds of the formula (XVII).

The various reactions described above are advantageously carried out in an inert organic solvent, for example toluene, xylene or mesitylene, in the presence of an inorganic base such as sodium hydroxide, potassium hydroxide, sodium carbonate or
potassium carbonate to neutralize the hydrohalic acid formed during the reactions. Sodium hydroxide is preferred.

The working temperatures of the reactions can vary, for example, from -20.degree. C. to 200.degree. C., preferably from -10.degree. C. to 190.degree. C., in particular from -10.degree. C. to 20.degree. C. for the substitution of the first
chlorine atom of cyanuric chloride; from 40.degree. C. to 90.degree. C. for the substitution of the second chlorine atom of cyanuric chloride; and from 90.degree. C. to 190.degree. C. for the substitution of the third chlorine atom of cyanuric
chloride.

In the above described processes, the reactions among the compounds of the formula (VII), (XX), (XXII), (XXVIII), (XXIX) or (XXX) and the compounds of the formulae (XV) and/or (XVI) may also be carried out in neat. In such a case, the compounds
of the formulae (XV) and/or (XVI) are used in a large excess to neutralize the hydrohalic acid formed during the reactions.

The various stages of the reactions can be carried out in a single reactor and in the same reaction medium, without isolating the intermediates or the reactions can be carried out after separation and, where appropriate, purification of the
intermediate compounds.

The reagents employed are commercially available or can be prepared in accordance with known processes. The diamine starting materials of the formulae (VIII) and (XXIV) may be prepared, for example, analogously to the method described in EP-A-33
663 and U.S. Pat. No. 4,526,972, taking Chemical Abstracts 72:32 718t, 75:130 747h and 83:194 575y into account.

The compounds of the formula (I) are very effective in improving the light, heat and oxidation resistance of organic materials, especially synthetic polymers and copolymers, in particular polypropylene fibres.

Polyolefins, i.e. the polymers of monoolefins exemplified in the preceding paragraph, preferably polyethylene and polypropylene, can be prepared by different, and especially by the following, methods:

a) radical polymerisation (normally under high pressure and at elevated temperature).

b) catalytic polymerisation using a catalyst that normally contains one or more than one metal of groups IVb, Vb, VIb or VIII of the Periodic Table. These metals usually have one or more than one ligand, typically oxides, halides, alcoholates,
esters, ethers, amines, alkyls, alkenyls and/or aryls that may be either .pi.- or .sigma.-coordinated. These metal complexes may be in the free form or fixed on substrates, typically on activated magnesium chloride, titanium(III) chloride, alumina or
silicon oxide. These catalysts may be soluble or insoluble in the polymerisation medium. The catalysts can be used by themselves in the polymerisation or further activators may be used, typically metal alkyls, metal hydrides, metal alkyl halides, metal
alkyl oxides or metal alkyloxanes, said metals being elements of groups Ia, IIa and/or IIIa of the Periodic Table. The activators may be modified conveniently with further ester, ether, amine or silyl ether groups. These catalyst systems are usually
termed Phillips, Standard Oil Indiana, Ziegler (-Natta), TNZ (DuPont), metallocene or single site catalysts (SSC).

2. Mixtures of the polymers mentioned under 1), for example mixtures of polypropylene with polyisobutylene, polypropylene with polyethylene (for example PP/HDPE, PP/LDPE) and mixtures of different types of polyethylene (for example LDPE/HDPE).

3. Copolymers of monoolefins and diolefins with each other or with other vinyl monomers, for example ethylene/propylene copolymers, linear low density polyethylene (LLDPE) and mixtures thereof with low density polyethylene (LDPE),
propylene/but-1-ene copolymers, propylene/isobutylene copolymers, ethylene/but-1-ene copolymers, ethylene/hexene copolymers, ethylene/methylpentene copolymers, ethylene/heptene copolymers, ethyleneloctene copolymers, propylene/butadiene copolymers,
isobutylene/isoprene copolymers, ethylene/alkyl acrylate copolymers, ethylene/alkyl methacrylate copolymers, ethylene/vinyl acetate copolymers and their copolymers with carbon monoxide or ethylene/acrylic acid copolymers and their salts (ionomers) as
well as terpolymers of ethylene with propylene and a diene such as hexadiene, dicyclopentadiene or ethylidene-norbornene; and mixtures of such copolymers with one another and with polymers mentioned in 1) above, for example
polypropylene/ethylene-propylene copolymers, LDPE/ethylene-vinyl acetate copolymers (EVA), LDPE/ethylene-acrylic acid copolymers (EAA), LLDPE/EVA, LLDPE/EAA and alternating or random polyalkylene/carbon monoxide copolymers and mixtures thereof with other
polymers, for example polyamides.

6. Copolymers of styrene or .alpha.-methylstyrene with dienes or acrylic derivatives, for example styrene/butadiene, styrene/acrylonitrile, styrene/alkyl methacrylate, styrene/butadiene/alkyl acrylate, styrenelbutadiene/alkyl methacrylate,
styrene/maleic anhydride, styrene/acrylonitrile/methyl acrylate; mixtures of high impact strength of styrene copolymers and another polymer, for example a polyacrylate, a diene polymer or an ethylene/propylene/diene terpolymer; and block copolymers of
styrene such as styrene/butadiene/styrene, styrene/isoprene/styrene, styrene/ethylenelbutylene/styrene or styrene/ethylene/propylene/styrene.

7. Graft copolymers of styrene or .alpha.-methylstyrene, for example styrene on polybutadiene, styrene on polybutadiene-styrene or polybutadiene-acrylonitrile copolymers; styrene and acrylonitrile (or methacrylonitrile) on polybutadiene;
styrene, acrylonitrile and methyl methacrylate on polybutadiene; styrene and maleic anhydride on polybutadiene; styrene, acrylonitrile and maleic anhydride or maleimide on polybutadiene; styrene and maleimide on polybutadiene; styrene and alkyl acrylates
or methacrylates on polybutadiene; styrene and acrylonitrile on ethylene/propylene/diene terpolymers; styrene and acrylonitrile on polyalkyl acrylates or polyalkyl methacrylates, styrene and acrylonitrile on acrylate/butadiene copolymers, as well as
mixtures thereof with the copolymers listed under 6), for example the copolymer mixtures known as ABS, MBS, ASA or AES polymers.

9. Polymers derived from .alpha.,.beta.-unsaturated acids and derivatives thereof such as polyacrylates and polymethacrylates; polymethyl methacrylates, polyacrylamides and polyacrylonitriles, impact-modified with butyl acrylate.

10. Copolymers of the monomers mentioned under 9) with each other or with other unsaturated monomers, for example acrylonitrile/butadiene copolymers, acrylonitrile/alkyl acrylate copolymers, acrylonitrile/alkoxyalkyl acrylate or
acrylonitrile/vinyl halide copolymers or acrylonitrile/alkyl methacrylate/butadiene terpolymers.

13. Polyacetals such as polyoxymethylene and those polyoxymethylenes which contain ethylene oxide as a comonomer; polyacetals modified with thermoplastic polyurethanes, acrylates or MBS.

14. Polyphenylene oxides and sulfides, and mixtures of polyphenylene oxides with styrene polymers or polyamides.

15. Polyurethanes derived from hydroxyl-terminated polyethers, polyesters or polybutadienes on the one hand and aliphatic or aromatic polyisocyanates on the other, as well as precursors thereof.

16. Polyamides and copolyamides derived from diamines and dicarboxylic acids and/or from aminocarboxylic acids or the corresponding lactams, for example polyamide 4, polyamide 6, polyamide 6/6, 6/10, 6/9, 6/12, 4/6, 12/12, polyamide 11,
polyamide 12, aromatic polyamides starting from m-xylene diamine and adipic acid; polyamides prepared from hexamethylenediamine and isophthalic or/and terephthalic acid and with or without an elastomer as modifier, for example
poly-2,4,4,-trimethylhexamethylene terephthalamide or poly-m-phenylene isophthalamide; and also block copolymers of the aforementioned polyamides with polyolefins, olefin copolymers, ionomers or chemically bonded or grafted elastomers; or with
polyethers, e.g. with polyethylene glycol, polypropylene glycol or polytetramethylene glycole as well as polyamides or copolyamides modified with EPDM or ABS; and polyamides condensed during processing (RIM polyamide systems).

18. Polyesters derived from dicarboxylic acids and diols and/or from hydroxycarboxylic acids or the corresponding lactones, for example polyethylene terephthalate, polybutylene terephthalate, poly-1,4-dimethylolcyclohexane terephthalate and
polyhydroxybenzoates, as well as block copolyether esters derived from hydroxyl-terminated polyethers; and also polyesters modified with polycarbonates or MBS.

19. Polycarbonates and polyester carbonates.

20. Polysulfones, polyether sulfones and polyether ketones.

21. Crosslinked polymers derived from aldehydes on th e one hand and phenols, ureas and melamines on the other hand, such as phenol/formaldehyde resins, urea/formaldehyde resins and melamine/formaldehyde resins.

26. Crosslinked epoxy resins derived from aliphatic, cycloaliphatic, heterocyclic or aromatic glycidyl compounds, e.g. products of diglycidyl ethers of bisphenol A and bisphenol F, which are crosslinked with customary hardeners such as
anhydrides or amines, with or without accelerators.

27. Natural polymers such as cellulose, rubber, gelatin and chemically modified homologous derivatives thereof, for example cellulose acetates, cellulose propionates and cellulose butyrates, or the cellulose ethers such as methyl cellulose; as
well as rosins and their derivatives.

29. Naturally occurring and synthetic organic materials which are pure

monomeric compounds or mixtures of such compounds, for example mineral oils, animal and vegetable fats, oil and waxes, or oils, fats and waxes based on synthetic esters (e.g. phthalates, adipates, phosphates or trimellitates) and also mixtures
of synthetic esters with mineral oils in any weight ratios, typically those used as spinning compositions, as well as aqueous emulsions of such materials.

The invention thus also relates to a composition comprising an organic material susceptible to degradation induced by light, heat or oxidation and at least one compound of the formula (I).

The organic material is preferably a synthetic polymer, more particularly one selected from the aforementioned groups. Polyolefins are preferred and polyethylene and polypropylene are particularly preferred.

A further embodiment of this invention is a method for stabilizing an organic material against degradation induced by light, heat or oxidation, which comprises incorporating into said organic material at least one compound of the formula (I).

The compounds of the formula (I) can be used in various proportions depending on the nature of the material to be stabilized, on the end use and on the presence of other additives.

In general, it is appropriate to use, for example, 0.01 to 5% by weight of the compounds of the formula (I), relative to the weight of the material to be stabilized, preferably 0.05 to 2% in particular 0.05 to 1%

The compounds of the formula (I) can be added, for example, to the polymeric materials before, during or after the polymerization or crosslinking of the said materials. Furthermore, they can be incorporated in the polymeric materials in the pure
form or encapsulated in waxes, oils or polymers.

In general, the compounds of the formula (I) can be incorporated in the polymeric materials by various processes, such as dry mixing in the form of powder, or wet mixing in the form of solutions or suspensions or also in the form of a masterbatch
which contains the compounds of the formula (I) in a concentration of 2.5 to 25% by weight; in such operations, the polymer can be used in the form of powder, granules, solutions, suspensions or in the form of latices.

The materials stabilized with the compounds of the formula (I) can be used for the production of mouldings, films, tapes, monofilaments, fibres, surface coatings and the like.

If desired, other conventional additives for synthetic polymers, such as antioxidants, UV absorbers, nickel stabilizers, pigments, fillers, plasticizers, corrosion inhibitors and metal deactivators, can be added to the organic materials
containing the compounds of the formula (I).

2.5. Nickel compounds, for example nickel complexes of 2,2'-thio-bis-[4-(1,1,3,3-tetramethylbutyl)phenol], such as the 1:1 or 1:2 complex, with or without additional ligands such as n-butylamine, triethanolamine or N-cyclohexyldiethanolamine,
nickel dibutyldithiocarbamate, nickel salts of the monoalkyl esters, e.g. the methyl or ethyl ester, of 4-hydroxy-3,5-di-tertbutylbenzylphosphonic acid, nickel complexes of ketoximes, e.g. of 2-hydroxy-4-methylphenyl undecylketoxime, nickel complexes of
1-phenyl-4-lauroyl-5-hydroxypyrazole, with or without additional ligands.

The weight ratio of the compounds of the formula (I) to the conventional additives may be for example 1:0.5 to 1:5.

The compounds of the formula (I) can also be used as stabilizers, especially as light stabilizers, for almost all materials known in the art of photographic reproduction and other reproduction techniques as e.g. described in Research Disclosure
1990, 31429 (pages 474 to 480).

The invention is illustrated in more detail by the following Examples. All percentages are by weight, unless otherwise indicated. The compounds of the following Examples 1, 2, 3, 4 and 8 are of particular interest.

A solution of 80.7 g (780 mmol) of 1,3-pentanediamine and 220 g (1417 mmol) of 2,2,6,6-tetramethyl-4-piperidone in 250 ml of ethanol is heated to 80.degree. C. The reaction mixture is maintained, under stirring, at 80.degree. C. for 2 hours.

Then, the solution is poured into an autoclave, added with 4 g of 5% Pt/C (% w/w) and the autoclave is pressurized with hydrogen.

The mixture is heated to 60.degree. C. and the pressure is maintained at 40 bars for 20 hours. Then, the mixture is cooled to room temperature, filtered and the solvent is evaporated in vacuo (40.degree. C./1 mbar). The oil residue is
distilled off.

The product obtained has a boiling point of 160.degree. C./0.1 mbar.

B) Preparation of the compound of the formula ##STR38##

A solution of 8.1 g (44 mmol) of cyanuric chloride in 80 ml of xylene is slowly added to a solution, cooled to -10.degree. C., of 50 g (131 mmol) of N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,3-pentanediamine in 500 ml of xylene.

After the addition, the mixture is heated to 0.degree. C. and a solution of 5.8 g (144 mmol) of sodium hydroxide in 12 ml of water is added. Then, the mixture is heated to room temperature and is maintained at this temperature for 1 hour under
stirring. Subsequently, the mixture is heated to reflux, being the added water and the reaction water distilled off by azeotropation. Then, the mixture is heated to 170.degree. C., by distilling off 300 ml of xylene. The mixture is maintained at
170.degree. C. for 3 hours. Then, the mixture is cooled to room temperature and washed twice with 50 ml of water. The organic phase is separated off, dried over anhydrous sodium sulfate, filtered and evaporated in vacuo (50.degree. C./1 mbar).

A solution of 24.1 g (130 mmol) of cyanuric chloride in 240 ml of xylene is slowly added to a solution, cooled to 0.degree. C., of 54.3 g (43 mmol) of the compound prepared according to B) in 200 ml of xylene. After the

addition, the mixture is stirred at room temperature for 20 hours. Then, a solution of 5.2 g (130 mmol) of sodium hydroxide in 20 ml of water is added. The mixture is maintained at room temperature for 2 hours under stirring. Then, the
mixture is washed twice with 100 ml of water, dried over anhydrous sodium sulfate, filtered and evaporated in vacuo (40.degree. C/1 mbar).

A mixture of 23 g (14 mmol) of the compound prepared according to C) in 126 g (593 mmol) of N-(2,2,6,6-tetramethyl-4-piperidyl)butylamine is heated to 180.degree. C. The reaction mixture is maintained at 180.degree. C. for 5 hours. Then, the
mixture is cooled to 60.degree. C. and 230 ml of xylene are added. A solution of 6.7 g (166 mmol) of sodium hydroxide in 40 ml of water is added. The aqueous phase is separated off and the organic solution is washed twice with 100 ml of water, dried
over sodium sulfate, filtered and evaporated in vacuo (70.degree. C/1 mbar).

The melting point of the product obtained is 184.degree.-194.degree. C.

A solution of 37 g (201 mmol) of cyanuric chloride in 370 ml of toluene is slowly added to a solution, cooled to -10.degree. C., of 153 g (401 mmol) of N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,3-pentanediamine in 1100 ml of toluene. During
the addition, the temperature is maintained at -10.degree. C. Subsequently, the mixture is heated to room temperature and maintained, under stirring, at room temperature for 3 hours.

Then, the mixture is cooled to 0.degree. C. and a solution of 32 g (802 mmol) of sodium hydroxide in 64 ml of water is added. After the addition, the mixture is heated again to room temperature, maintained, under stirring, at room temperature
for 12 hours, heated to 80.degree. C. and maintained at 80.degree. C. for 3 hours.

Then, the mixture is cooled to room temperature, being the aqueous phase separated off.

A solution of 74.1 g (402 mmol) of cyanuric chloride in 700 ml of toluene is slowly added to the mixture, cooled to 0.degree. C.

After the addition, the mixture is heated to room temperature and maintained at room temperature, under stirring, for 24 hours.

A solution of 16.1 g (402 mmol) of sodium hydroxide in 75 ml of water is added, being the mixture stirred at room temperature for further 4 hours. Then, the aqueous phase is separated off, the organic phase is washed twice with 100 ml of water
and toluene is evaporated in vacuo (70.degree. C./1 mbar).

Subsequently, 1344 g (6.3 mol) of N-(2,2,6,6-tetramethyl-4-piperidyl)butylamine are added and the mixture is heated to 180.degree. C. and maintained at 180.degree. C., under stirring, for 5 hours. The mixture is cooled to 60.degree. C. and
300 ml of toluene are added. A solution of 60 g (1.50 mol) of sodium hydroxide in 150 ml of water is added and, after stirring, the aqueous phase is separated off. The organic solution is washed twice with 200 ml of water, dried over anhydrous sodium
sulfate, filtered and evaporated in vacuo (70.degree. C./1 mbar).

The melting point of the product obtained is 173.degree.-178.degree. C.

A solution of 36.8 g (200 mmol) of cyanuric chloride in 370 ml of toluene is slowly added to a solution, cooled to -10.degree. C., of 153 g (401 mmol) of N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,3-pentanediamine in 1100 ml of toluene. During
the addition, the temperature is maintained at -10.degree. C. Then, the mixture is heated to room temperature and maintained, under stirring, at room temperature for 3 hours. The mixture is cooled to 0.degree. C. and a solution of 32 g (800 mmol) of
sodium hydroxide in 64 ml of water is added. After the addition, the mixture is stirred for 12 hours at room temperature, heated to 80.degree. C. and maintained at 80.degree. C. for 3 hours. Subsequently, the mixture is cooled to room temperature,
being the aqueous phase separated off. A solution of 73.8 g (400 mmol) of cyanuric chloride in 690 ml of toluene is slowly added to the organic mixture cooled to 0.degree. C. Then, the mixture is heated to room temperature and maintained under stirring
at the above temperature for 24 hours. A solution of 16 g (400 mmol) of sodium hydroxide in 75 ml of water is added and the mixture is stirred at room temperature for further 4 hours. The aqueous phase is separated off and the organic phase is washed
twice with 100 ml of water.

Then, a solution of 51.7 g (400 mmol) of dibutylamine in 100 ml of toluene is slowly added and, after 1 hour of stirring at room temperature, a solution of 32 g (800 mmol) of sodium hydroxide in 100 ml of water is added. Subsequently, the
mixture is heated to 80.degree. C. for 2 hours, cooled again to room temperature and the aqueous phase is separated off. The organic phase is washed twice with 100 ml of water and toluene is evaporated in vacuo (70.degree. C./1 mbar).

The residue is taken up with 1560 g (7.3 mol) of N-(2,2,6,6-tetramethyl-4-piperidyl)-butylamine and heated to 180.degree. C. Then, the mixture is maintained under stirring at 180.degree. C. for 5 hours. After cooling to 60.degree. C., 800 ml
of toluene are added. Then, a solution of 24 g (600 mmol) of sodium hydroxide in 130 ml of water are added and the aqueous phase is separated off. After washing twice with 300 ml of water, the organic phase is dried over anhydrous sodium hydroxide,
filtered and evaporated in vacuo (70.degree. C/1 mbar).

The product obtained has a melting point of 132.degree.-139.degree. C.

A mixture of 60.1 g (36 mmol) of the compound prepared according to Example 16 in 400 g (3 mol) of N-(2,2,6,6-tetramethyl-4-piperidyl)butylamine is heated to 180.degree. C. and maintained at 180.degree. C. for 5 hours. Then, the mixture is
cooled to 60.degree. C. and 200 ml of toluene are added. A solution of 17.2 g (432 mmol) of sodium hydroxide in 100 ml of water are added and the organic phase is separated off.

After washing twice with 200 ml of water, the organic solution is dried over anhydrous sodium sulfate, filtered and evaporated in vacuo (70.degree. C./1 mbar).

The product obtained has a melting point of 148.degree.-152.degree. C.

A mixture of 40 g (20 mmol) of the compound of Example 2 in 400 ml of cyclohexane is heated to reflux. Then, 0.2 g of MoO.sub.3 is added. 116 g (890 mmol) of 70% (% w/w) aqueous solution of t-butyl hydroperoxide are slowly added. Further 0.2 g
of MoO.sub.3 are added and the water is distilled off by azeotropation. After the removal of the water, the mixture is heated to 125.degree. C. in a pressure resistant flask and maintained at 125.degree. C. for 4 hours.

Then, the mixture is cooled to 50.degree. C. and MoO.sub.3 is filtered off. The organic solution is stirred with a solution of 25 g (190 mmol) of sodium sulfite in 100 ml of water for 1 hour and washed twice with 100 ml of water. Subsequently,
the organic solution is dried over anhydrous sodium sulfate, filtered and evaporated in vacuo (40.degree. C./1 mbar).

The product obtained has a melting point of 177.degree.-187.degree. C.

A solution of 5 g (13 mmol) of N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,3-pentanediamine in 30 ml of toluene is slowly added to a solution, cooled to 0.degree. C., of 4.8 g (26 mmol) of cyanuric chloride in 70 ml of toluene. After the
addition, the mixture is heated to room temperature and maintained at room temperature for 1 hour under stirring. Then, the mixture is cooled to 0.degree. C. and a solution of 2 g (42 mmol) of sodium hydroxide in 4 ml of water is added. The mixture is
heated again to room temperature, maintained under stirring at room temperature for further 1 hour, being 50 ml of toluene and 10 ml of water added. After stirring for further 10 hours, the organic phase is washed twice with 50 ml of water. A solution
of 5.4 g (14 mmol) of N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,3-pentanediamine in 50 ml of toluene is slowly added to the solution, cooled at 0.degree. C. After the addition, the mixture is heated to room temperature and maintained at room
temperature for 1 hour.

Then, a solution of 1.1 g (29 mmol) of sodium hydroxide in 3 ml of water is added and the mixture is heated to 80.degree. C. The mixture is maintained at 80.degree. C. for further 5 hours, under stirring. After cooling to room temperature, the
mixture is washed with water. A solution of 2.2 g (12 mmol) of cyanuric chloride in 22 ml of toluene is slowly added to a solution, cooled at 0.degree. C. After the addition, the mixture is heated to room temperature and maintained at room temperature
for 14 hours. A solution of 0.5 g (12 mmol) of sodium hydroxide in 1 ml of water is added and the mixture is stirred for 1 hour. After washing twice with 50 ml of water, the organic phase is evaporated in vacuo (40.degree. C./1 mbar) and the residue
is taken up with 42.5 g (200 mmol) of N-(2,2,6,6-tetramethyl-4-piperidyl)butylamine. Then, the mixture is heated to 180.degree. C. and maintained at 180.degree. C. for 5 hours under stirring. After cooling to 60.degree. C., a solution of 2.6 g (65
mmol) of sodium hydroxide in 6 ml of water is added. The mixture is stirred for 1 hour, added with 60 ml of toluene, washed twice with 50 ml of water, dried over anhydrous sodium sulfate, filtered and evaporated in vacuo (70.degree. C./1 mbar).

The product obtained has a melting point of 176.degree.-186.degree. C.

A mixture of 20 g (8.1 mmol) of the compound of Example 4 in 200 ml of t-amyl alcohol and 6.6 g (218 mmol) of paraformaldehyde is heated under stirring to 80.degree. C. Then, 4.3 g (93 mmol) of formic acid is added over a 15 minutes period and
left to react for 2 hours. The mixture is cooled down to 25.degree. C. and a solution of 4.46 g (111 mmol) of sodium hydroxide in 50 ml of water is added under stirring and left to react for 30 minutes. The organic layer is washed with water until
neutrality. The solvent is evaporated in vacuo (50.degree. C./1 mbar) and 19.5 g of a pale yellow solid is obtained.

2.5 g of the stabilizer shown in Table 1, 1 g of tris(2,4-di-tert-butylphenyl) phosphite, 1 g of calcium monoethyl-3,5-di-tert-butyl-4-hydroxybenzyl phosphonate, 1 g of calcium stearate and 2.5 g of titanium dioxide are mixed in a slow mixer with
1000 g of polypropylene powder having a melt index of 12 g/10 min (measured at 230.degree. C. and 2.16 kg).

The mixtures are extruded at 200-230.degree. C. to obtain polymer granules which are then converted into fibres using a pilot-type apparatus (.RTM.Leonard-Sumirago (VA); Italy) and operating under the following conditions:

Extruder temperature: 230-245.degree. C.

Head temperature: 255-260.degree. C.

Draw ratio: 1:3.5

Linear density: 11 dtex per filament

The fibres prepared in this way are exposed, after mounting on a white cardboard, in a 65 WR Weather-O-Meter (ASTM D2565-85) with a black panel temperature of 63.degree. C.

For samples taken after various times of exposure to the light, the residual tenacity is measured using a constant-speed-tensometer and the exposure time in hours needed to halve the initial tenacity (T.sub.50) is

then calculated.

For purposes of comparison, fibres prepared under the same conditions as described above but without adding the stabilizers of the present invention, are also exposed.

Light-stabilizing action in polypropylene tapes. 1 g of the stabilizer shown in Table 2, 1 g of tris(2,4-di-tert-butylphenyl) phosphite, 0.5 9 of pentaerythritol-tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] and 1 g of calcium
stearate are mixed in a turbomixer with 1000 g of polypropylene powder having a melt index of 2.1 g/10 mi (measured at 230.degree. C. and 2.16 kg).

The mixtures are extruded at 200-220.degree. C. to give polymer granules which are subsequently converted to stretched tapes of 50 am thickness and 2.5 mm width, using a semi-industrial type of apparatus (.RTM.Leonard-Sumirago (VA)-Italy) and
working under the following conditions:

Extruder temperature: 210-230.degree. C.

Head temperature: 240-260.degree. C.

Stretch ratio: 1:6

The tapes, thus prepared, are mounted on a white card and exposed in a Weather-O-Meter 65 WR (ASTM D2565-85) with a black panel temperature of 63.degree. C.

The residual tenacity is measured, by means of a constant velocity tensometer, on a sample taken after various light exposure times; from this, the exposure time (in hours) required to halve the initial tenacity (T.sub.50) is measured.

By way of comparison, tapes prepared under the same conditions as indicated above, but without the addition of the stabilizers of the present invention, are exposed.

1 g of each of the compounds listed in Table 3 and 1 g of calcium stearate are mixed in a slow mixer with 1000 g of polypropylene powder having a melt index of 4.3 (measured at 230.degree. C. and 2.16 Kg).

The mixtures are extruded at 220.degree. C. to give polymer granules which are then converted into plaques of 1 mm thickness by injection-moulding at 220.degree. C.

The plaques are then punched using a DIN 53451 mould and the specimens obtained are exposed in a forced circulation air oven maintained at a temperature of 135.degree. C.

The specimens are checked at regular intervals by folding them by 180.degree. in order to determine the time (days) required for fracturing them.

5.625 g of the stabilizer shown in Table 4, 13.500 g of Pigment Blue 15 "Flush" (50% mixture in polyethylene) and 25.875 g of polypropylene powder (having a melt index of approximately 14 measured at 230.degree. C. and 2.16 Kg) are added to fill
a .RTM.Haake internal mixer at room temperature (.RTM.Haake Buchler Rheochord System 40 using a 60 cc 3 piece Rheomixer with cam blades). The cam blades are rotating at 5 RPM (revolutions per minute). A ram closed the bowl under a weight of 5 kg. The
temperature is increased to 180.degree. C. and held at 180.degree. C. The total time is 30 minutes.

The mixture is removed while at 180.degree. C. after 30 minutes and cooled down to room temperature. The mixture so obtained--called the "concentrate"--will be used again.

0.900 g of this concentrate, 3.600 g of titanium dioxide "Flush" (50% mixture in polyethylene), and 40.500 g of polypropylene powder (having a melt index of approximately 14 measured at 230.degree. C. and 2.16 Kg) are added to a .RTM.HAAKE mixer
bowl at 160.degree. C. The cam blades are rotating at 20 RPM. A ram closes the bowl under a weight of 5 kg. The temperature is increased to 170.degree. C. and the RPM is increased to 125. The total time is 30 minutes.

The molten mixture is removed at 170.degree. C., transferred to a hand held tool at room temperature and transformed into a round plaque 1 mm.times.25 mm in diameter. The mixture now so obtained is called the "letdown" and the plaque the
"letdown plaque."

The above processing conditions are designed to simulate the manufacture of concentrates (masterbatches) of pigments and stabilizers and the subsequent let-down (dilution) into finished plastic articles.

A high delta E indicates pigment agglomeration and poor dispersion. A delta E of 0.5 or less will not be seen as different by the eye.